Wheelchair

ABSTRACT

A wheelchair capable of ensuring the safety of an occupant by securely restraining the occupant&#39;s body when the wheelchair is placed in an automobile, even in the event of collision. The wheelchair may have a seat body in which an occupant is seated, seat belts capable of restraining the occupant&#39;s body, and seat belt retractors which apply tension to the seat belts in the winding-up direction and are provided with locking mechanisms for locking the movement of the respective seat belts in the withdrawing direction when tension exceeding a predetermined value is applied to the seat belts.

BACKGROUND

The present invention relates to a wheelchair which permits an occupant to move in his or her seated state and to a wheelchair suitably used to be put in a vehicle such as an automobile.

Nowadays, wheelchairs are widely used as simple vehicles which are necessary for permitting an occupant such as an injured person with wounded legs or a handicapped person with impaired legs to move in the seated state. The structure of a commonly used wheelchair is a foldable structure which comprises a pipe frame, which rotatably supports main wheels and front auxiliary wheels and is openable and closable in the lateral direction, and a bottom sheet and a back sheet which are made of cloth and are stretched between pipes of the pipe frame.

Since such an occupant in a wheelchair may be not able to brace his or her legs, the occupant hardly keeps balance on the bottom sheet and the back sheet while being seated in the wheelchair. Therefore, a wheelchair is desired to have the function of holding the occupant's body securely when used, such as during an outing or the like. For this, wheelchairs provided with a seat belt for holding the occupant's body have been conventionally proposed. An example of such a device is disclosed in Japanese Patent Unexamined Publication 2000-316911 (incorporated by reference herein).

Recently, popularity has increased with automobiles that have been provided with equipment for permitting a wheelchair, with the occupant seated therein, to be brought into a cargo compartment of the automobile in order to save the wheelchair occupant the effort of transferring to a seat of the automobile from the wheelchair. However, the structure of the wheelchair, as described in Japanese Patent Unexamined Publication 2000-316911, can not restrain the occupant's body sufficiently against a strong impact produced by a sudden stop or collision of the automobile when the wheelchair is put in the automobile and thus can not ensure the safety of the occupant, even with the seat belt.

SUMMARY OF THE INVENTION

An object of an embodiment of the present invention is to provide a wheelchair capable of protecting an occupant by securely restraining the occupant's body during a collision involving an automobile, in which the wheelchair is located.

According to an embodiment of the present invention, a wheelchair includes a seat in which an occupant is seated, seat belts capable of restraining the body of the occupant, and at least one seat belt retractor for applying tension to said seat belts in a winding-up direction.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only, and are not restrictive of the invention as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features, aspects, and advantages of the present invention will become apparent from the following description, appended claims, and the accompanying exemplary embodiments shown in the drawings, which are briefly described below.

FIG. 1 is a perspective view, taken obliquely from above, of a wheelchair according to the embodiment of the present invention.

FIG. 2 is a perspective view of the wheelchair of FIG. 1, taken obliquely from below.

FIG. 3 is a side view of the wheelchair of FIG. 1.

FIG. 4 is a front view of the wheelchair of FIG. 1.

FIG. 5 is an bottom view of the wheelchair of FIG. 1.

FIG. 6 is an enlarged view of a buckle accommodation portion in a state that a common buckle is accommodated.

DETAILED DESCRIPTION

Hereinafter, an embodiment of the present invention will be described with reference to the attached drawings.

As shown in FIG. 1, according to one embodiment of the present invention, a wheelchair 1 generally includes a seat body 2, a pair of main wheels 3 provided on both lower sides at a rear portion of the seat body 2, a pair of front auxiliary wheels 4 provided on both lower sides at a front portion of the seat body 2, a pair of footrests 5 provided on both side at the front portion of the seat body 2, a handle 6 provided on the backside of the seat body 2, five seat belts 7, 8, 9, 10, and 11 which are withdrawn from corresponding portions of the seat body 2, and seat belt retractors 12, 13, 14, 15, and 16 (shown by broken lines in FIG. 2 and FIG. 5) connecting the respective seat belts 7 through 11 to the seat body 2.

First, the function of the wheelchair 1 will be schematically described, according to an embodiment of the present invention. An occupant is seated in the seat body 2 and puts his or her feet on the footrests 5, whereby the occupant is in the normal seated state. Further from this state, the respective seat belts 7 through 11 are withdrawn from the respective seat belt retractors 12 through 16 and are suitably fastened, whereby the occupant's body can be securely restrained to the seat body 2. The occupant can move the wheelchair by himself or herself by rotating the main wheels 3 with his or her hands. A care provider can easily move the wheelchair 1 by grasping the handle 6, regardless of whether or not an occupant is in the wheelchair 1.

According to an embodiment of the present invention, when the wheelchair 1 of this embodiment is placed in and fixed to a cargo compartment of an automobile by an attachment, as will be described later, the occupant's body can be securely restrained to the wheelchair 1. Accordingly, even when subjected to strong impact produced by sudden stop or collision of the automobile, the wheelchair can restrain the occupant's body sufficiently and thus ensures the safety of the occupant.

Hereinafter, the respective sections exhibiting the above functions will be described in detail.

First, the seat body 2 will be described, according to an embodiment of the present invention. The seat body 2 includes a seating portion 17 on which the occupant is seated, a backrest portion 18 which receives the upper body of the occupant, a headrest portion 19 which is positioned on the upper end of the backrest portion 18 and receives the head of the occupant, mounting portions (not shown) which are located on the lower surface of the seating portion 17 and to which main wheel shaft supporting portions 21 supporting the main wheels 3 and a main wheel shaft 20 are mounted by bolts or the like, side walls 22 which are positioned to extend obliquely from the both sides of the seating portion 17 to the front lower sides, and armrest portions 23 which are positioned on both sides at rear and upper portions of the side walls 22. These are all made of lightweight materials. For example, these parts may be made of CFRP (Carbon-Fiber Reinforced Plastics, hereinafter referred to as “CFRP”) and are formed integrally as a monocoque chair-like structure. It should be noted that the material is not limited to CFRP and may be other composite material such as GFRP (Glass-Fiber Reinforced Plastics), or resin material. All of the corners of the seat body 2 may be curved to make the entire configuration have stream surfaces and streamlines. However, the headrest portion 19 may not to be formed in the monocoque structure and may be a separate structure which is telescopic or vertically shiftable relative to the other portion. Similarly, the armrest portions 23 may not be formed in the monocoque structure and may also be separate structures which are attached to the other portion by bolts or the like.

In the wheelchair of the present invention, it is preferable that the monocoque structure includes a mounting portion which is located on the lower surface of said seating portion for mounting a main wheel shaft supporting portion supporting a main wheel shaft. Accordingly, the entire strength of the wheelchair is further improved so as to increase the durability against impact, thereby further ensuring the safety of the occupant.

Since the seat body 2 receiving the occupant in a seated position and functioning as a main structure member connecting the respective parts of the wheelchair 1 may be formed in the monocoque structure, the entire strength of the wheelchair 1 may be improved so as to increase the durability against impact and, in addition, the occupant's body can be reliably and securely restrained via the seat belt retractors 12 through 16 and the seat belts 7 through 11.

Since the seat body 2 may be formed in a configuration composed of stream surfaces and streamlines, stress concentration is hardly generated even when being subjected to a large load, such as an impact, so that the structure has very high durability. Though the seat body 2 is preferably formed integrally by high-strength CFRP as mentioned above, the material for the seat body 2 is not limited thereto and, of course, the seat body 2 may be made of another high-strength material such as high-strength aluminum. As for the monocoque structure of the seat body 2, durability required to withstand impact is achieved when at least the seating portion 17, the backrest portion 18, and the headrest portion 19 are integrally formed. However, the durability is significantly improved in case of the monocoque structure in which the mounting portions to which the main wheel shaft supporting portions 21 are mounted are also formed integrally, like the wheelchair of this embodiment.

The structure of the backrest portion 18 has high strength to withstand a large load from the seat belts 8, 9 during a collision when the wheelchair is in an automobile. A rear surface 18 a (opposite to the surface to be in contact with the back of the occupant) of the backrest portion 18 is provided with ribs 24 formed on the left and right sides thereof to extend in the vertical longitudinal direction, thereby further improving the strength of the backrest portion 18. Therefore, the upper body of the occupant, which undergoes the most drastic movement during an impact, can be reliably restrained. Particularly, the ribs 24 extending in the vertical direction as illustrated cause the backrest portion 18 to be hardly bent, even if a large load is applied in the anteroposterior direction. That is, the backrest portion 18 is structured to be strong particularly against frontal impact. The illustrated ribs 24 may have a hollow box-like structure, but are not limited thereto. The ribs 24 may be composed of angle bars or channel bars.

The seating portion 17 and the backrest portion 18 may be arranged to have an angle of 90 degrees or more therebetween so that the backrest portion 18 tilts backward as shown in FIG. 3. For example, an angle of about 120 degrees may be used. The angle of 90 degrees or more between the seating portion 17 and the backrest portion 18 enables the occupant to sit in a comfortable position such that the occupant can lean his or her upper body on the backrest portion.

Additionally, ballasts (not shown) may be placed on respective portions so that when the backrest portion 18 is arranged to tilt backward when the occupant is seated, the weight balance is set such that the position of center-of-gravity of the wheelchair (indicated by a point A in FIG. 3) is higher than the main wheel shaft 20 and lower than the center point (indicated by a point B in FIG. 3) of the lumbar of the occupant. According to this structure, the center of gravity of the wheelchair 1 is stable when the occupant is seated and the occupant can easily balance by moving his or her lumbar, thereby preventing the occupant from toppling down, even when receiving impact.

Returning to FIG. 1, the headrest portion 19 is positioned so that the headrest portion 19 is in contact with the back of the head of the occupant when seated. A headrest mat, not shown, may be attached to the center of the headrest portion 19. In this case, the impact against the head is effectively absorbed even when receiving the impact due to a collision as mentioned above.

The main wheel shaft supporting portions 21 support the main wheel shaft 20 such that the main wheel shaft 20 projects laterally from the seat body 2, penetrates the main wheels 3, and rotatably supports the main wheels 3. The main wheel shaft supporting portions 21 bear most of the weight of the occupant and transmit the load to the main wheels 3 via the main wheel shaft 20. Therefore, reinforcement members are mostly concentrated on the main wheel shaft supporting portions 21 among the seat body 2.

The armrest portions 23 are portions on which the occupant puts his or her arms and which are formed integrally with mud guards covering the upper portions of the main wheels 3, respectively. Therefore, even when the wheelchair 1 is structured to be compact by locating the main wheels 3 near the seating portion 17, the occupant is prevented from touching tires (as will be described later) of the main wheels 3, thereby providing safe and hygienic use and providing comfortable use because the occupant can put his or her arms on the armrest portions comfortably.

A leg belt 25 (for example, composed of an expandable belt, marketed as Magic-belt) is provided to extend between the side walls 22 in the lateral direction above the footrests 5. The leg belt 25. receives the calves of the occupant and supports to prevent the legs of the occupant from slipping down even when the occupant has weak legs.

Attachments 26 are fixed to the outer surfaces of rear portions of the side walls 22 by bolts, respectively. Each attachment 26 is provided with a slit 27 opening at or near the front. A securing device fixed to the cargo compartment of the automobile (not shown) is attached to the slits 27, thereby securing the wheelchair 1 to the cargo compartment.

Now, the main wheels 3 will be described. Each main wheel 3 is provided with a bearing inside thereof (the bearing may be provided on the main wheel shaft 20 not the main wheel 3) and comprises a hub 28 rotatably supported to the main wheel shaft 20, a plurality of (four, in this embodiment) spokes which extend radially from the hub 28, a rim 30 which connects the spokes and is disposed coaxially with the hub 28, a rubber tire 31 fitted to the outer periphery of the rim 30, and a push rim 32 which is an annular ring having substantially the same diameter as the rim 30 and is connected to and spaced apart from the rim 30 outwardly in the lateral direction. The occupant can operate the wheelchair 1 to move forward, move backward, turn left, and turn right by grasping the push rims 32 on both sides and rotating the push rims 32 to and fro.

Next, the front auxiliary wheels 4 will be described. Each front auxiliary wheel 4 may include a wheel 34, a rubber tire 33 fitted to the outer periphery of the wheel 34, and a caster fork 35 to which the wheel 34 is rotatably supported. The caster fork 35 is supported at the lower end of the side wall 22 of the seat body 2 such that the caster fork 35 can rotate about a vertical shaft. The front auxiliary wheels 4 having the aforementioned structure support load on the front side of the wheelchair 1 and facilitate the smooth movement of the wheelchair 1 in a desired direction.

The footrests 5 will be described below. The footrests 5 may include flat plates which are supported pivotally in the vertical direction between the side walls 22 of the seat body 2. When the footrests 5 are lowered, the footrests 5 are stopped by stoppers, not shown, at a position that the footrests 5 face each other in the horizontal direction. The footrests 5 are installed in so-called flip-up style so as to allow free pivotal movement thereof above their horizontal positions. When the footrests 5 are lowered and fixed in the horizontal direction, and the legs of the occupant are put on the footrests 5, the legs of the occupant seated in the wheelchair are stable. When the occupant is about to get on and off the wheelchair 1, the occupant is allowed to stand directly on the ground near the seating portion 17 by lifting the footrests 5. This prevents the wheelchair 1 from falling if the occupant stands on the footrests 5.

The handle 6 will be described below. The handle 6 (handle member) may be a rod-like member as shown in FIG. 2 and may be arranged to extend substantially horizontally in parallel with the backrest portion 18. A generally-used conventional handle is composed of backrest pipes, i.e., a pair of cantilevered grippers disposed on the both rear sides of the backrest portion to extend in the anteroposterior horizontal direction. On the other hand, the handle 6 of this embodiment may be formed in a C-like shape extending between the left side and the right side. Therefore, the care provider positioned behind the wheelchair 1 can grip more conveniently, thereby facilitating the pushing action and the pulling action. In addition, the handle can be gripped on the center line of the wheelchair 1 by one hand, thereby facilitating the handling of the wheelchair 1 when no occupant is seated, i.e., the wheelchair is vacant.

Hereinafter, the seat belts 7 through 11 and the seat belt retractors 12 through 16 will be described. The five seat belts 7 through 11 may be allowed to be withdrawn through holes 36, 37, 38, 39, and 40 formed in the seat body 2 so that one of the seat belts can be withdrawn through a hole 36 formed at a central portion of the seating portion 17, two of the other seat belts can be withdrawn through holes 37, 38 formed near the armrest portions 23 of the respective side walls 22, and remainder of the two seat belts can be withdrawn through two holes 39, 40 formed at the same level in the backrest portion 18, respectively. The seat belt 8 to be withdrawn through the hole 37 formed in the side wall 22 on the right side, as seen from the occupant, is provided at its end with a common buckle 41, while the other four seat belts 7, 9, 10, and 11 are provided at their ends with tongues 42 which can be latched to the common buckle 41.

When the seat belts 7 through 11 are withdrawn and the respective tongues 42 are latched to the common buckle 41, the seat belts 7 through 11 extend radially from the common buckle 41 as shown in FIG. 4. The occupant is restrained at his or her shoulders to the backrest portion 18 by the upper two seat belts 10 and 11, is restrained at his or her abdomen to the backrest portion 18 by the side two seat belts 8 and 9, and is restrained at his or her hips to the seating portion 17 by the lower one seat belt 7.

All of the seat belts 7 through 11 may be connected to the seat body 2 via the seat belt retractors 12 through 16, respectively as shown in FIG. 2. The seat belt retractors 12 through 16 may retract the respective seat belts 7 through 11 with light natural force and allow the respective seat belts 7 through 11 to be withdrawn for predetermined lengths. The seat belt retractors 12 through 16 always apply tension in the winding-up direction to the respective seat belts 7 through 11. Therefore, when the seated occupant puts on the seat belts 7 through 11, the seat belts 7 through 11 can restrain the occupant's body with suitable tension. When the seat belts 7 through 11 are unlatched from the common buckle 41 and thus become free, the seat belt retractors 12 through 16 wind up the respective seat belt 7 through 11 automatically. Moreover, the seat belt retractors 12 through 16 have locking mechanisms for locking the movement of the seat belts 7 through 11 in the withdrawing direction when sudden tension is applied to the respective seat belts 7 through 11.

Accordingly, when the wheelchair 1 is put in the automobile and a strong impact is applied to the occupant's body due to sudden stop or collision of the automobile, the occupant's body can be securely restrained to the wheelchair 1 by the tension of the seat belts 7 through 11 in the winding-up direction, thereby ensuring the safety of the occupant. When a further strong impact is applied, sudden tension is applied to the seat belts 7 through 11 so that the seat belts 7 through 11 are locked from being withdrawn from the seat belt retractors 12 through 16 by the locking mechanisms, whereby the occupant's body is securely restrained to the wheelchair 1 by the seat belts 7 through 11, thus ensuring the safety of the occupant. When the wheelchair 1 is brought down from the automobile and the seat belts 7 through 11 are taken off, the seat belt retractors 12 through 16 automatically wind up and accommodate the seat belts 7 through 11, thereby releasing the occupant from the burden due to the seat belts 7 through 11 so as to make the occupant comfortable and to permit the smooth movement of the occupant off of the wheelchair 1.

The number of the seat belt retractors may be two or more, not one. It is preferable that each of the seat belts is provided with a seat belt retractor, such as in this embodiment. In this case, the restraint of the occupant's body by the seat belt while receiving impact is further ensured, thereby further ensuring the safety of the occupant. Though a five-point-type restraint by five seat belts like this embodiment is preferable, a four- or less-point-type restraint may be used, depending on conditions.

In the wheelchair of the present invention, it is preferable that the number of the seat belt retractors is two or more.

The plurality of seat belt retractors further ensure the restraint of the occupant's body by the seat belts when receiving impact, thereby further ensuring the safety of the occupant.

In the wheelchair of the present invention, it is preferable that the seat belt retractor is mounted on the back side of the seat. That is, the seat belt retractor is mounted on the back side of the seat and the strength of the seat is increased.

Therefore, even when the occupant receives a strong impact produced by sudden stop or collision of the automobile when the wheelchair is in an automobile, the seat belt retractor securely applies tension to the seat belt in the winding-up direction without coming off the seat, even when the seat is damaged, thereby restraining the occupant's body.

In the wheelchair 1 of this embodiment, the seat belt retractors 12 through 16 may be concentrated and placed near the main wheel shaft supporting portions 21 as shown in FIG. 5. Particularly, the seat belt retractors 13 through 16 may be placed over the rear surface 18 of the back (opposite side of the seating side) of the seat. The reinforcement members may be concentrated on the rear surface 18 and the main wheel shaft supporting portions 21, which have increased strength as mentioned above, and the seat belt retractors 12 through 16, which may be located near the line of the main wheel shaft, can be directly attached to the reinforcement members. Therefore, even when a sudden tension is applied to the seat belts 7 through 11, the seat belt retractors 12 through 16 securely lock without coming off the seat body 2, thereby securely restraining the occupant's body.

In the wheelchair of the present invention, it is preferable that the seat belt retractor is disposed near the main wheel shaft supporting portion. That is, the seat belt retractor can be attached to some or all of the reinforcement members disposed near the main wheel shaft supporting portion, creating increased strength because of the reinforcement members. Therefore, the seat belt retractor securely locks the seat belts even when sudden tension is applied to the seat belts, thereby securely restraining the occupant's body.

The seat belt retractors 12 through 16 may be of any type among various types used for seats in automobiles having the aforementioned locking unction and automatic winding function. In this embodiment, the seat belt retractors 12 through 16 have limiter mechanisms, not shown. The limiter mechanisms stop the automatic winding to stop the tongues 42 of the seat belts 7 through 11 at respective predetermined positions before the holes 36 through 40, thereby preventing the seat belts 7 through 11 from being retracted too much to make the seat belts 7 through 11 hard to be withdrawn or impossible to be withdrawn. Instead of the limiter mechanism, stoppers impossible to pass through the holes 36 through 40 may be attached to the tongues 42, respectively, thereby preventing the seat belts 7 through 11 from being retracted too much.

Near the hole 37 through which the right-side seat belt 8 with the common buckle 41, a buckle accommodation portion 43 may be formed in the side wall 22 of the seat body 2 into a concave shape having such a size to allow the common buckle 41 to be fitted inside thereof. Accordingly, when the seat belts 7 through 11 are wound up and the common buckle 41 is retracted, the common buckle 41 is accommodated in the side wall 22 as shown in FIG. 6, thereby preventing the common buckle 41 from disturbing the occupant.

The wheelchair 1 of this embodiment having the aforementioned structure can provide more comfortable and safe use during normal use on the ground as compared to the conventional one. In addition, when the wheelchair 1 is put in the automobile, the occupant's body can be securely restrained as the case where the occupant's body is seated on a normal seat of the automobile and restrained by the automobile seat belt. That is, the wheel chair 1 of this embodiment has a function suitable for use in an automobile.

Given the disclosure of the present invention, one versed in the art would appreciate that there may be other embodiments and modifications within the scope and spirit of the invention. Accordingly, all modifications attainable by one versed in the art from the present disclosure within the scope and spirit of the present invention are to be included as further embodiments of the present invention. The scope of the present invention is to be defined as set forth in the following claims. 

1. A wheelchair comprising: a seat for supporting an occupant; seat belts capable of restraining the body of the occupant; and at least one seat belt retractor for winding up and applying tension to at least one of the seat belts.
 2. The wheelchair as claimed in claim 1, wherein the number of seat belt retractors is two or more.
 3. The wheelchair as claimed in claim 1, wherein said seat belt retractor is mounted on the back side of said seat.
 4. The wheelchair as claimed in claim 1, wherein said seat belt retractor has a locking mechanism which locks the movement of said seat belt in a withdrawing direction when tension exceeding a predetermined value is applied to said seat belt.
 5. The wheelchair as claimed in claim 1, wherein said seat has a monocoque structure in which a seating portion on which the occupant is seated, a backrest portion which receives the upper body of the occupant, and a headrest portion which is positioned on the upper end of the backrest portion and receives the head of the occupant are formed integrally.
 6. The wheelchair as claimed in claim 5, wherein the monocoque structure includes a mounting portion which is located on a lower surface of said seating portion for mounting a main wheel shaft supporting portion for supporting a main wheel shaft.
 7. The wheelchair as claimed in claim 6, wherein said seat belt retractor is disposed near said main wheel shaft supporting portion.
 8. The wheelchair as claimed in claim 5, wherein at least one rib is disposed on the backrest portion to extend along the longitudinal direction of the backrest portion.
 9. The wheelchair as claimed in claim 5, further comprising a handle member which is disposed substantially horizontally in parallel with said backrest portion.
 10. The wheelchair as claimed in claim 1, wherein an armrest portion for receiving an arm of said occupant and a mud guard covering an upper portion of a main wheel are integrally formed.
 11. The wheelchair as claimed in claim 5, wherein said seating portion and said backrest portion are arranged to have an angle of 90 degrees or more therebetween.
 12. The wheelchair as claimed in claim 1, wherein a position of center-of-gravity of the wheelchair is higher than a main wheel shaft and lower than a center point of the lumbar of the occupant when the occupant is seated.
 13. The wheelchair as claimed in claim 1, wherein the number of said seat belt retractors equals the number of seat belts.
 14. The wheelchair as claimed in claim 5, wherein the seating portion, the backrest portion, and the headrest portion are made of carbon-fiber reinforced plastic, glass-fiber reinforced plastic, composite material, or resin.
 15. The wheelchair as claimed in claim 1, wherein one seat belt includes a common buckle and a remaining set of seat belts include tongues.
 16. The wheelchair as claimed in claim 15, further comprising a buckle accommodation portion for the common buckle.
 17. The wheelchair as claimed in claim 1, further comprising a device for attachment to a securing device of an automobile for securing the wheelchair within the automobile.
 18. A wheelchair comprising: a seat in which an occupant is seated; seat belts capable of restraining the body of the occupant; and at least one seat belt retractor for applying tension to said seat belts in a winding-up direction; wherein the seat includes apertures for allowing the seat belts to pass through the seat. 